1. Field of the Invention
Spectacles frame glazing with particular reference to improvements in method and apparatus for measuring and fitting lenses in spectacles lens rims of molded, cast and/or machined plastic materials.
2. Discussion of the Prior Art
Ophthalmic lenses are edged to fit the rims of spectacles frames with machines using patterns which are provided by the frame manufacturer or made up from the spectacles frames as disclosed in U.S. Pat. No. 3,170,374, for example. Alternatively, the spectacles rims themselves may function as the edging pattern as in U.S. Pat. No. 3,899,851 or 4,027,434. Other examples of the latter procedure can be seen in U.S. Pat. Nos. 3,555,739; 3,672,855; 3,786,600; and 4,096,684.
In the above cases distortion in spectacles lens rims, e.g. oversize in one meridian and undersize in another and/or irregularities such as unintended bends, are duplicated in the edged lens which leaves the finally glazed frame uncorrected, i.e. with its original variations from nominal size and/or shape.
Other lens edging procedures which rely upon lens size measurement taken across the lens rim opening do not reflect frame distortions and similarly lead to poorly glazed frames when variations between actual and nominal frame shapes occur.
In view of the foregoing, it is an object of this invention to provide novel method and apparatus for use in glazing spectacles frames with corrections of variations between actual and nominal frame shapes, i.e. to provide method and apparatus for measuring correct spectacles lens size independently of rim irregularities.
Other objects and advantages of the invention will become apparent from the following description.